Water overflow

[TheWub]

Hello,
2016 Thor Vegas 25.3
We are hooked up to city water right now and I noticed that we have water coming out of the potable water supply filler opening just above it. I’ve never noticed it overflow before. What could cause this to happen? And, if you know, can I stop it?
Thanks!

[Trkyte@msn.com]

Check valve in the water pump isn’t working.
Shut off the city water then run water with the onboard pump. Sometimes the check valve gets stuck open.
When you stop the water the pump should also stop.

[ducksface]

The op problem is one of the reasons we always run off of our internal tank and not shore water.
And
consistent pressure.
No froze or busted hose.
No dogs get a chance to pee on our hose.

As said, disconnect from shore water.
Fix it when you get a chance at good weather or at home.
What you've told us is not a critical thing. Just a nuisance.

[Elite Washington]

Originally Posted by ducksface

The op problem is one of the reasons we always run off of our internal tank and not shore water.
And
consistent pressure.
No froze or busted hose.
No dogs get a chance to pee on our hose.

As said, disconnect from shore water.
Fix it when you get a chance at good weather or at home.
What you've told us is not a critical thing. Just a nuisance.

We always run off of the pump. This is one of my biggest fears is at night or when I am away some cheap plastic part will break and I will have a flooded coach. Seen it a campground one time I felt so bad for the campers.

[lwmcguir]

The only time I run off city water pressure is wash day

Otherwise I keep at least 1/3 tank full

There are many reasons this makes sense in an RV